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1979 Mazda RX7

FRNKNRX license plate

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79 Rex

The paint job I'm contemplating

Banzai Hot Wheel
It's a Hot Wheel!

More Pictures!
Dyno Charts!

I aquired this critter in late '94, with a cranks/no start/no run condition. a friend of mine had transplanted the engine from his recently wrecked '81 GSL model RX-7 into this runs-but-smokes '79 GS chassis. It ran for a while, then quit. After sitting in his parents' garage for about a year, he decided to sell it, and I happened to be in a position to cough up the $350 he was asking. After trailering it to my parents' place (where my father already has a car farm going!), Dad and I fiddled with it a bit, and discovered that the coils were recieving no power. We hot wired them directly to the battery, and lo! and behold, it started and ran!

I acquired a service manual and took a good look at the wiring diagrams. Turns out that there are a pair of fusible links in the steering column harness. One of them was loose, and that was the whole problem. It took a little longer to get it running right, since my friend had swapped the entire engine over, wiring harness and all, from the '81. Did you know that an 81 RX-7 harness will plug into a 79 harness and work (mostly) after blowing a couple of fuses? I acquired the correct harness, vacuum spider, and carb from a wrecking yard, and got it as close to right as possible. Now the automatic choke release works properly, and all the guages worked. I did modify the harness to accomodate the internally-regulated later model alternator. And have since made other updates and upgrades.In addition to those, it has recieved a K&N drop in replacement filter. Other that those mods, and Energy Suspension polyurethane bushings in the front and Tokico HP shocks/struts all around, it's basically stock. Heck most of the mods are just updates to later model stock parts!It was my daily driver up until January '97, when it didn't start one day. Thought I'd lost an apex seal. For those of you not into rotary engines, that's analagous to losing the rings in a piston engine - no compression = no workee. I was fearing the rebuild - rotaries are a little more expensive to rebuild - like around $1200 - 2500 for a stock rebuild - but I was going to do it!. There's nothing quite like the hum of a rotary engine, and you can't beat their HP to physical size ratio. Fortunately, after it sat for a year, I took it to somebody a bit more knowledgable.
Turns out, apparently, that carbon buildup can cause the apex seals to not do so (seal). The Rotary Shop in Fort Worth cleaned it up on 4/98, and Boom! good as new. Anybody out there know how they did it? I really wanna know, so I don't have to spend $250 if it does it again! Email me if you know!In January '99, I upgraded to the electronic ignition from an 81-85 RX, and figured out with the help of a fellow rotorhead why performance was so lame. With a 79 carb on an 81 manifold, the vacuum ports don't line up, therefore, no secondary action on the four-barrels. A couple of zip ties later, mechanical secondaries were kludged, and now it'll go. Top speed went from 85 to 105. MUCH more satisfying!She makes almost 100HP at the rear wheels now. The only deviation from stock on the motor is the free-flowing K&N filter, the catalytic converters emptied themselves (or somebody did it for me before I bought the thing), and the later model electronic ignition. No header, stock (81) exhaust and muffler, air pump and all! According to my references, it's only rated for 104HP at the flywheel. Not sure what I did, but I like it. See the Dyno Chart!

This summer ('99), I installed the later model brakes and limited slip rearend from a GSL model. This gave me discs all around, and the potential for adjustable shocks/struts later.Future plans include those aforementioned Tokico Illuminas, Eibach or Suspension Techniques lowered springs, a Ground Control adjustable front sway bar, and a full exhaust sytem with header, maybe Mind-Train or Racing Beat. Other possibilities include a ported motor and other goodies!I've aquired a mildly ported '80 engine. This will be going into the '79, along with an '84 transmission (better, shorter shifter). For one thing, all the vacuum ports should actually line up between the intake, engine, and carb, which means the vacuum secondaries should work as advertised! Second, this will leave the '81 engine free to go into the '84 roller I acquired from my bud Tim Schuh.

In 2000 so far, the car has aquired a rear spoiler (3-piece wraparound style), and Yokohama AVS Intermediate in 205/60-13. These are great dual-purpose tires, with excellent wet and dry traction, and one of the few performance (V-rated!) tires in the smaller sizes to fit stock first gen RX-7 wheels. I use them as my street and autocross tires, as i can't quite afford true race rubber for weekend cone-dodging.I've also redone the radio bezel in 3/16" aluminum, allowing for aftermarket temp, oil, and volts guages in the design. I lost my EQ, but I like being able to eyeballl the engine with more-accurate-than-stock guages. I used Autometer Pro-Comp Ultra-Lite 2-1/16" guages. These are very sweet looking all aluminum black on silver guages with orange needles. With the amber light boots in, their illumination almost matches the factory (81) guages in the car.

10/02: Uh-oh!
Minor complications: I lost one or more Apex seals on the way home from work on Friday 10/11/02. Hot-rodded around a u-turn that I have to make (which provides for very nice power slides), and lost power after straightening up. It was still running, but sluggish and rough, even with the clutch in. Checked ignition first, replaced leading ignition pieces with known-good wires and frech plugs - still no go. Pulled the plugs to listen to the rotors. Got PHAP! PHAP! PHAP! on the rear rotor; fwish, fwish, fwish on the front :( I squirted 6 oz. of ATF into the chambers (2 oz for each face) to see if maybe the seals had carboned up again. Let it sit overnight. Same noises in the morning, so I pulled the exhaust manifold to see if I could see or fell anything. After a bit of fiddling, I could feel a piece missing from one of the apex seals. Bah! And just after I put in a new clutch!
Fotunately, I bought a supposedly-good '80 12A some time ago. Guess it's time for it to go in now. Hope it really is good!

11/02: Hoo-ah!
It lives again! The '80 engine seems to be good. While I was in there, I put in an '84 A/C condenser in preperation for refitting the A/C system to something that actually uses o-rings for sealing (the '79 port-installed system only had flare fittings!), a 3-core radiator from an automatic car, and I put the original under-the-radiator oil cooler back and removed the rediculous air-water beehive thing 9which was only on there because I made a mistake in radiator selection when I was a noob.) Somehow, along the way, the air pump and ACV got lost :) and I used an '80 intake manifold (that came with the engine) that had been port-matched to the center iron. Seems to run pretty stron, but I need to get it dyno'd to really tell, as that may be my notoriously optimistic Wishful Thinking brand butt-dyno.I notice that I forgot to mention the new transmission up above. The clutch began slipping a couple of months ago, so I took the opportunuty to replace the original third-gear-synchro-going-out tranny with an '84 unit that I acquired some time ago, along with a Rotary Performance Standard Clutch Kit - slightly better than stock, and *way* better than that weak-ass Autozone special that I had on there. Tranny and clutch went back in with the new engine, of course.

5/03: Bigger Brakes!
The '79 now sports a full GSL-SE suspension, donated by the Blue Bomb, for larger brake-age, and a usable wheel bolt pattern. Verbage here. Pics here.

12/04: 16-inch wheels and new tires!
With the GSL-SE suspension comes the increased availability of new wheels. I was prepping the 626 Turbo wheels while wearing out the tires I had borrowed from my bud Tim Schuh, when Tim forwarded a contact from a fellow autocrosser who had sold his second-gen RX-7, and was looking to sell his old wheels and fresh tires cheap. Fortunately, his FC was a 4-bolt car, and a deal was struck for not much more than I ould have paid for cheap 205/50-15s for the 626 wheels!
Pictures here.

I've created a page detailing how to replicate most of the modifications I've made to the car. To see how I accomplished these feats, see my Early RX-7 Modifications Page!

Late 2008:
Fragged the replacement engine. As near as I can tell it ran out of oil before I caught it, and wore out the side or apex seals. It was burning more oil that usual for a rotary. Most likely the oil-control o-rings were failing. One day on the highway it just started slowing down. I was able to get it off of the freeway onto an off ramp, where it quit. Later I was able to pop-start it by rolling down the hill, but it ran badly, very much low on power, and it smoked all over. I noticed while driving it home (with my wife following) that I had no oil pressure. I don't know if all the oil went before the initial failure, or while driving it afterward with all the smoke, to be honest. We had to stop and add oil, then pull-start it to get moving again. Made it all the way home after that. The icing on the cakeis that weeks later I got a "gross polutter" notice in the mail from the State of Texas. Some responsible citizen had reported me for all the smoke!

At the moment, she sits quietly in the driveway. I pulled off the 16" wheels with NEW tires and traded them with the stock wheels that were on the Grey Mouse in the garage, because it's up on jackstands, hopefully saving the tires.

In the meantime, I was driving the Cutlass, but it decided to eat the 1-2 clutches in the Turbo-Hydramatic 350 automatic. To keep rolling, I refurbished the '90 RX-7 GXL I acquired a while back. It's a bit ugly, due to some minor body damage and mis-matched replacement panels, but it runs and drives great!

To see more pictures of my baby, go here!


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